title: Routine micromethod for the determination of vitamin K1 in human plasma.
abstract: BACKGROUND
  A selective and sensitive high-performance liquid chromatographic method with fluorescence detection after postcolumn reduction is described for the routine measurement of vitamin K1 in plasma samples of 100 µL of volume.
  
  
  METHODS
  Liquid-liquid extraction was used for the sample preparation with vitamin K2 as an internal standard. For the chromatographic separation, a standard C18 column was applied. The calibration range used was from 2 to 500 ng/mL.
  
  
  RESULTS
  At the low level (5 ng/mL), a coefficient of variation of 14.9% was observed interday in the quality control samples, whereas at the intermediate (50 ng/mL) and high (200 ng/mL) levels such of 6.8% and 8.7% were found.
  
  
  CONCLUSIONS
  The method has proven robust and convenient for the analysis of samples from clinical pharmacological studies.
authors.affiliation: *Department of Clinical Pharmacology, University Medical Centre of the Georg August University Göttingen, Göttingen, Germany; and †Institute of Pharmacology of Natural Products and Clinical Pharmacology, University of Ulm, Ulm, Germany.
authors.forename: Ingolf
authors.initials: I
authors.lastname: Meineke
authors.forename: Cornelia
authors.initials: C
authors.lastname: Willnow
authors.forename: Julia
authors.initials: J
authors.lastname: Stingl
authors.forename: Jürgen
authors.initials: J
authors.lastname: Brockmöller
mesh_terms: D000818:Animals; D000933:Antifibrinolytic Agents / Q000097:blood*; D002138:Calibration; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D011786:Quality Control; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D010837:Vitamin K 1 / Q000097:blood*
chemical_list: D000933:Antifibrinolytic Agents; D010837:Vitamin K 1